Over current protection circuit and liquid crystal display

ABSTRACT

Disclosed is an over current protection circuit, comprising N left over current protection sub circuit and N right over current protection sub circuit, applied in the GOA circuit having a dual driving function, each of the left GOA units and right GOA units can be driven by the clock control signals outputted respectively by the corresponding left and right level shifting sub circuits; the first left level shifting sub circuit and the first left GOA unit are coupled through the first left clock line, the first left over current protection sub circuit, which is coupled to the first left clock line in series or arranged between the first left clock line and the first left level shifting sub circuit controls the first left level shifting sub circuit to stop outputting the first left clock control signal when the first left driving current is larger than a predetermined current threshold value.

CROSS REFERENCE

This application claims the priority of Chinese Patent Application No.201710823714.6, entitled “Over current protection circuit and liquidcrystal display”, filed on Sep. 13, 2017, the disclosure of which isincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a display technology field, and moreparticularly to an over current protection circuit and a liquid crystaldisplay.

BACKGROUND OF THE INVENTION

The GOA (Gate Driver on Array) technology is a kind of skill whichmanufactures the Thin Film Transistor (TFT) gate scan drive circuit onthe TFT array substrate to replace the drive chip manufactured by theexternal silicon chip. The gate voltage for the TFTs of each row in theliquid crystal display can be provided by the GOA circuit. In the GOAcircuit, a level shifter is generally used to generate a clock controlsignal to control on and off of the TFTs of each row.

In the manufacturing process of the liquid crystal display, if thesealant of the liquid crystal display is not tight or there is dustinside the panel, it is easy to cause the output signal of the levelshifter to be short-circuited. Currently, in order to prevent the shortcircuit of the clock control signal in the panel, an over currentprotection (OCP) circuit is generally provided to turn off the levelshifter to prevent the liquid crystal display panel from being burnedout. However, for the liquid crystal display panel utilizing the dualdriving mode, the current OCP detection is to control the entire panelwithout signal output with the level shifter when some portion insidethe panel is detected to be short-circuited. Then, the entire can onlybe scrapped.

SUMMARY OF THE INVENTION

The present invention provides an over current protection circuit and aliquid crystal display, which can achieving the working mode as the gatedriver on array (GOA) is in short circuit such that the GOA at one sideis in short circuit and the GOA at the other side still can worksnormally.

First, the present invention provides an over current protectioncircuit, applied in a substrate array row driving gate driver on array(GOA) circuit having a dual driving function, wherein the GOA circuithaving the dual driving function comprises N left GOA units, N right GOAunits, a left level shifting circuit and a right level shifting circuit,wherein the over current protection circuit comprises a left overcurrent protection circuit and a right over current protection circuit,the left over current protection circuit comprises N left over currentprotection sub circuits and the right over current protection circuitcomprises N right over current protection sub circuits; the left levelshifting circuit comprises N left level shifting sub circuits and theright level shifting circuit comprises N right level shifting subcircuits, each of the left GOA units is driven by a corresponding leftlevel shifting sub circuit and each of the right GOA units is driven bya corresponding right level shifting sub circuit, N is an positiveinteger;

a first left GOA unit and a first left level shifting sub circuit arecoupled through a first left clock line, a first left over currentprotection sub circuit is coupled to the first left clock line and thefirst left level shifting sub circuit; a first right GOA unit and afirst right level shifting sub circuit are coupled through a first rightclock line, a first right over current protection sub circuit is coupledto the first right clock line and the first right level shifting subcircuit; the first left GOA unit is any one of the N left GOA units andthe first right GOA unit is any one of the N right GOA units;

when the first left level shifting circuit works, the first left levelshifting circuit generates a first left clock control signal to beoutputted to the first left GOA unit through the first left clock line;when the first right level shifting circuit works, the first right levelshifting circuit generates a first right clock control signal to beoutputted to the first right GOA unit through the first right clockline; the first left clock control signal has the same timing as thefirst right clock control signal;

the first left over current protection sub circuit detects a first leftdriving current on the first left clock line and controls the first leftlevel shifting sub circuit to stop working when the first left drivingcurrent is larger than a predetermined current threshold value; thefirst right over current protection sub circuit detects a first rightdriving current on the first right clock line and controls the firstright level shifting sub circuit to stop working when the first rightdriving current is larger than the predetermined current thresholdvalue.

The first left over current protection sub circuit outputs a first leftstopping control signal to the first left level shifting sub circuitwhen first left driving current is larger than the predetermined currentthreshold value to control the first left level shifting sub circuit tostop working;

The first right over current protection sub circuit outputs a firstright stopping control signal to the first right level shifting subcircuit when first right driving current is larger than thepredetermined current threshold value to control the first right levelshifting sub circuit to stop working.

The first left level shifting sub circuit comprises a first leftcontrolling circuit and a first left amplifying circuit, when the firstleft level shifting sub circuit normally works, the first leftamplifying circuit converts a clock signal inputted to the first leftcontrolling circuit by a clock controller into the first left clockcontrol signal; the first left controlling circuit controls the firstleft amplifying circuit to stop working when the first left controllingcircuit receives the first left stopping control signal;

The first right level shifting sub circuit comprises a first rightcontrolling circuit and a first right amplifying circuit, when the firstright level shifting sub circuit works, the first right amplifyingcircuit converts a clock signal inputted to the first right controllingcircuit by a clock controller into the first right clock control signal;the first right controlling circuit controls the first right amplifyingcircuit to stop working when the first right controlling circuitreceives the first right stopping control signal.

The over current protection circuit first provided by the presentinvention comprises N left over current protection sub circuit and Nright over current protection sub circuit and can be applied in the GOAcircuit having the dual driving function. The GOA circuit comprises Nleft GOA units, N right GOA units. Each of the left GOA units and rightGOA units can be driven by the clock control signals outputtedrespectively by the corresponding left level shifting sub circuit andcorresponding right level shifting sub circuit, wherein the first leftlevel shifting sub circuit and the first left GOA unit are coupledthrough the first left clock line, the first left over currentprotection sub circuit coupled to the first left clock line and thefirst left level shifting sub circuit controls the first left levelshifting sub circuit to stop working when the first left driving currenton the first left clock line is larger than the predetermined currentthreshold value; the first right level shifting sub circuit and thefirst right GOA unit are coupled through the first right clock line, thefirst right over current protection sub circuit coupled to the firstright clock line and the first right level shifting sub circuit controlsthe first right level shifting sub circuit to stop working when thefirst right driving current on the first right clock line is larger thanthe predetermined current threshold value. Accordingly, when the firstleft clock line of the first left GOA unit is in short circuit, thefirst right clock control signal outputted to the first right GOA unitwill not be affected and the TFT corresponding to the GOA unit of therow still can work normally. By implementing the embodiment of thepresent invention, it can be realized that the clock line at one side ofthe GOA circuit is in short circuit and the clock line at the other sidestill can work normally without bringing other risks.

Second, the present invention provides another over current protectioncircuit, applied in a substrate array row driving gate driver on array(GOA) circuit having a dual driving function, wherein the GOA circuithaving the dual driving function comprises N left GOA units, N right GOAunits, a left level shifting circuit and a right level shifting circuit,wherein the over current protection circuit comprises a left overcurrent protection circuit and a right over current protection circuit,the left over current protection circuit comprises N left over currentprotection sub circuits and the right over current protection circuitcomprises N right over current protection sub circuits, both the leftover current protection sub circuits and the right over currentprotection sub circuits are fuses; the left level shifting circuitcomprises N left level shifting sub circuits and the right levelshifting circuit comprises N right level shifting sub circuits, each ofthe left GOA units is driven by a corresponding left level shifting subcircuit and each of the right GOA units is driven by a correspondingright level shifting sub circuit, N is an positive integer;

a first left GOA unit and a first left level shifting sub circuit arecoupled through a first left clock line, a first left over currentprotection sub circuit is coupled to the first left clock line inseries; a first right GOA unit and a first right level shifting subcircuit are coupled through a first right clock line, a first right overcurrent protection sub circuit is coupled to the first right clock linein series; the first left GOA unit is any one of the N left GOA unitsand the first right GOA unit is any one of the N right GOA units;

when the first left level shifting circuit works, the first left levelshifting circuit generates a first left clock control signal to beoutputted to the first left GOA unit through the first left clock line;when the first right level shifting circuit works, the first right levelshifting circuit generates a first right clock control signal to beoutputted to the first right GOA unit through the first right clockline; the first left clock control signal has the same timing as thefirst right clock control signal;

the first left over current protection sub circuit is fused when thefirst left clock control signal on the first left clock line is largerthan a predetermined current threshold value to stop the first leftlevel shifting sub circuit outputting the first left clock controlsignal to the first left GOA unit; the first right over currentprotection sub circuit is fused when the first right clock controlsignal on the first right clock line is larger than the predeterminedcurrent threshold value to stop the first right level shifting subcircuit outputting the first right clock control signal to the firstright GOA unit.

Both the first left over current protection sub circuit and the firstright over current protection sub circuit are recoverable fuses.

The first left level shifting sub circuit comprises a first leftcontrolling circuit and a first left amplifying circuit, when the firstleft level shifting sub circuit normally works, the first leftamplifying circuit converts a clock signal inputted to the first leftcontrolling circuit by a clock controller into the first left clockcontrol signal; the first left controlling circuit controls the firstleft amplifying circuit to stop working when the first left controllingcircuit receives the first left stopping control signal;

The first right level shifting sub circuit comprises a first rightcontrolling circuit and a first right amplifying circuit, when the firstright level shifting sub circuit works, the first right amplifyingcircuit converts a clock signal inputted to the first right controllingcircuit by a clock controller into the first right clock control signal;the first right controlling circuit controls the first right amplifyingcircuit to stop working when the first right controlling circuitreceives the first right stopping control signal.

The over current protection circuit second provided by the presentinvention can be applied in the GOA circuit having the dual drivingfunction. The GOA circuit comprises N left GOA units, N right GOA units.Each of the left GOA units and right GOA units can be driven by theclock control signals outputted respectively by the corresponding leftlevel shifting sub circuit and corresponding right level shifting subcircuit; the over current protection circuit comprises N left fuses andN right fuses, wherein the first left level shifting sub circuit and thefirst left GOA unit are coupled through the first left clock line, thefirst left fuse coupled to the first left clock line in series controlsthe first left level shifting sub circuit to stop outputting the firstleft clock control signal to the first left GOA unit when the first leftdriving current on the first left clock line is larger than thepredetermined current threshold value; the first right level shiftingsub circuit and the first right GOA unit are coupled through the firstright clock line, the first right fuse coupled to the first right clockline in series controls the first right level shifting sub circuit tostop outputting the first right clock control signal to the first rightGOA unit when the first right driving current on the first right clockline is larger than the predetermined current threshold value.Accordingly, when the first left clock line of the first left GOA unitis in short circuit, the first right clock control signal outputted tothe first right GOA unit will not be affected and the GOA unit of therow still can provide the gate voltage to the TFTs of the row, normally.By implementing the embodiment of the present invention, it can berealized that the clock line at one side of the GOA circuit is in shortcircuit and the clock line at the other side still can work normally.

Third, the present invention further provides a liquid crystal displayincluding the over current protection circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the presentinvention or prior art, the following figures will be described in theembodiments are briefly introduced. It is obvious that the drawings aremerely some embodiments of the present invention, those of ordinaryskill in this field can obtain other figures according to these figureswithout paying the premise.

FIG. 1 is a diagram of an over current protection circuit disclosed bythe embodiment of the present invention;

FIG. 2 is a diagram of another over current protection circuit disclosedby the embodiment of the present invention;

FIG. 3 is a diagram of one another over current protection circuitdisclosed by the embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

For better explaining the technical solution and the effect of thepresent invention, the present invention will be further described indetail with the accompanying drawings in the specific embodiments. It isclear that the described embodiments are part of embodiments of thepresent application, but not all embodiments. Based on the embodimentsof the present invention, all other embodiments to those of ordinaryskill in the premise of no creative efforts obtained, should beconsidered within the scope of protection of the present invention.

Besides, the following descriptions for the respective embodiments arespecific embodiments capable of being implemented for illustrations ofthe present invention with referring to appended figures. For example,the terms of up, down, front, rear, left, right, interior, exterior,side, etcetera are merely directions of referring to appended figures.Therefore, the wordings of directions are employed for explaining andunderstanding the present invention but not limitations thereto.

In the description of the invention, which needs explanation is that theterm “installation”, “connected”, “connection” should be broadlyunderstood unless those are clearly defined and limited, otherwise, Forexample, those can be a fixed connection, a detachable connection, or anintegral connection; those can be a mechanical connection, or anelectrical connection; those can be a direct connection, or an indirectconnection with an intermediary, which may be an internal connection oftwo elements. To those of ordinary skill in the art, the specificmeaning of the above terminology in the present invention can beunderstood in the specific circumstances.

Besides, in the description of the present invention, unless with beingindicated otherwise, “plurality” means two or more. In the presentspecification, the term “process” encompasses an independent process, aswell as a process that cannot be clearly distinguished from anotherprocess but yet achieves the expected effect of the process of interest.Moreover, in the present specification, any numerical range expressedherein using “to” refers to a range including the numerical valuesbefore and after “to” as the minimum and maximum values, respectively.In figures, the same reference numbers will be used to refer to the sameor like parts.

The embodiment of the present invention provides an over currentprotection circuit and a liquid crystal display, which can achieving theworking mode as the gate driver on array (GOA) is in short circuit suchthat the GOA at one side is in short circuit and the GOA at the otherside still can works normally without bringing other risks. The detaildescriptions are respectively introduced below.

Please refer to FIG. 1. FIG. 1 is a diagram of an over currentprotection circuit disclosed by the embodiment of the present invention.As shown in FIG. 1, the over current protection circuit described in theembodiment comprises a left over current protection circuit 10 and aright over current protection circuit 20. The left over currentprotection circuit 10 comprises N left over current protection subcircuits (the first left over current protection sub circuit 11, thesecond left over current protection sub circuit 12, . . . , the Nth leftover current protection sub circuit 1N shown in FIG. 1). The right overcurrent protection circuit 20 comprises N right over current protectionsub circuits (the first right over current protection sub circuit 21,the second right over current protection sub circuit 22, . . . , the Nthright over current protection sub circuit 2N shown in FIG. 1).

The over current protection circuit is applied in a substrate array rowdriving gate driver on array (GOA) circuit having a dual drivingfunction. The substrate array row driving gate driver on array (GOA)circuit having the dual driving function comprises N left GOA unitswhich are cascade coupled (the first left GOA unit, the second left GOAunit, . . . , the Nth left GOA unit shown in FIG. 1, wherein N is aninteger larger than 1), N right GOA units which are cascade coupled (thefirst right GOA unit, the second right GOA unit, . . . , the Nth rightGOA unit shown in FIG. 1), a left level shifting circuit 30 and a rightlevel shifting circuit 40. The first left GOA unit and the first rightGOA unit jointly drive the same scan line, the first left GOA unit andthe first right GOA unit jointly drive the same scan line and so on. TheN left GOA units and the N right GOA units are respectively arranged atleft side and the right side of the display panel to implement dualdriving to all the scan lines. Namely, the N left GOA units drive allthe scan lines from left to right and meanwhile, the N right GOA unitsdrive all the scan lines from right to left. The left GOA unit of eachstage and the right GOA unit of each stage correspond to the thin filmtransistors (TFTs) of the same row. Namely, the left GOA unit and theright GOA unit of the same stage jointly act for driving the pixels ofthe same row.

The left level shifting circuit 30 comprises N left level shifting subcircuits (the first left level shifting sub circuit 31, the second leftlevel shifting sub circuit 32, . . . , the Nth left level shifting subcircuit 3N shown in FIG. 1). The right level shifting circuit 40comprises N right level shifting sub circuits (the first right levelshifting sub circuit 41, the second right level shifting sub circuit 42,. . . , the Nth right level shifting sub circuit 4N shown in FIG. 1).Each left GOA unit is driven by the clock control signal outputted bythe corresponding left level shifting sub circuit and each right GOAunit is driven by the clock control signal outputted by thecorresponding right level shifting sub circuit. The timings (sequences)of the clock control signals received by the left GOA unit and the rightGOA unit of the same stage which are at two sides are the same.

In the following, the left GOA unit and the right GOA unit correspondingto the TFTs of the first row are taken as an illustration. The firstleft GOA unit is any one of the N left GOA units, and the first rightGOA unit is any one of the N right GOA units. Specifically, the firstleft GOA unit and the output end of the first left level shifting subcircuit 31 are coupled through the first left clock line and the firstleft over current protection sub circuit 11 connects the first leftclock line and the control end of the first left level shifting subcircuit 31; the first right GOA unit and the output end of the firstright level shifting sub circuit 31 are coupled through the first rightclock line and the first right over current protection sub circuit 21connects the first right clock line and the control end of the firstright level shifting sub circuit 41; the first left level shifting subcircuit 31 is a left level shifting sub circuit corresponding to thefirst left GOA unit and the first right level shifting sub circuit 41 isa left level shifting sub circuit corresponding to the first right GOAunit.

Optionally, the first left level shifting sub circuit 31 and the firstleft over current protection sub circuit 11 can be arranged inside onelevel shifting chip; the first right level shifting sub circuit 41 andthe first right over current protection sub circuit 21 are arrangedinside another level shifting chip. The second left level shifting subcircuit 32 and the second left over current protection sub circuit 12can be arranged inside a third level shifting chip and so on.Optionally, the left level shifting circuit 30 comprising the N leftlevel shifting sub circuits and the left over current protection circuit10 comprising the N left over current protection sub circuits arearranged in one level shifting chip. The right level shifting circuit 40comprising the N right level shifting sub circuits and the right overcurrent protection circuit 20 comprising the N right over currentprotection sub circuits are arranged in another level shifting chip. Or,the left level shifting circuit 30, the left over current protectioncircuit 10, the right level shifting circuit 40 and the right overcurrent protection circuit 20 are all arranged in the same levelshifting chip.

When the first left level shifting sub circuit 31 works, the first leftlevel shifting sub circuit 31 generates a first left clock controlsignal CK1-L. The first left clock control signal CK1-L is outputted tothe first left GOA unit through the first left clock line to control onand off of the TFTs of the row.

Similarly, when the first right level shifting sub circuit 41 works, thefirst right level shifting sub circuit 41 generates a first right clockcontrol signal CK1-R. The first right clock control signal CK1-R isoutputted to the first right GOA unit through the first right clockline. The timings (sequences) of the first left clock control signalCK1-L and the first right clock control signal CK1-R are the same.

The first left over current protection sub circuit 11 detects a firstleft driving current I1-L on the first left clock line and controls thefirst left level shifting sub circuit 31 to stop working when the firstleft driving current I1-L is larger than a predetermined currentthreshold value such that the first left clock line enters the shortcircuit protection state. Namely, the first left level shifting subcircuit 31 stops generating the first left clock control signal CK1-L tothe first left GOA unit. Then, the output of the first left levelshifting sub circuit 31 is in Hi-Z (high-impedance state). Then, for theTFT array of the first row in the liquid crystal display panel, the dualdriving mode becomes the single driving mode and the liquid crystaldisplay panel still can work normally but only the effect of the paneldisplay may be slightly lower to reduce the panel level. Specifically,the state different from the high-impedance state is a normal state. inthe normal state, the first left level shifting sub circuit 31 generatesthe first left clock control signal CK1-L of low level or high level tobe outputted to the first left GOA unit.

Similarly, the first right over current protection sub circuit 21detects a first right driving current I1-R on the first right clock lineand controls the first right level shifting sub circuit 41 to stopworking when the first right driving current I1-R is larger than thepredetermined current threshold value.

Furthermore, the first left over current protection sub circuit 11detects a first left driving current on the first left clock line andcontrols the first left level shifting sub circuit 31 to stop outputtinga first left stopping control signal to control the first left levelshifting sub circuit 31 to stop working with the first left stoppingcontrol signal. Similarly, the first right over current protection subcircuit 21 detects a first right driving current on the first rightclock line and controls the first right level shifting sub circuit 41 tostop stops outputting a first right stopping control signal. The firstleft stopping control signal can control the first right level shiftingsub circuit 41 to stop working.

Specifically, the first left over current protection sub circuit 11 isillustrated and may comprise a current detector and a current comparatorwhich are sequentially connected in series. One end of the currentdetector is coupled to the first left clock line. The output end of thecurrent comparator is coupled to the control end of the first levelshifting sub circuit 31. Certainly, the structure is not limitedthereto. The current detector can be used to detect the first leftdriving current I1-L on the first left clock line. The currentcomparator compares the first left driving current I1-L detected by thecurrent detector with a predetermined current threshold value and theresult of the comparison is fed back (or outputted) to the control endof the first left level shifting sub circuit 31. The first left levelshifting sub circuit 31 is controlled to stop outputting the first leftclock control signal CK1-L to the first left GOA unit when the firstleft driving current I1-L on the first left clock line is larger thanthe predetermined current threshold value.

With the above analysis, the left clock control signal and the rightclock control signal provided to the first left GOA unit and the firstright GOA unit in the embodiment of the present invention are generatedby two independent level shifting sub circuits. These two level shiftingsub circuits are respectively controlled by one over current subcircuit. Mainly, it is to respectively control these two level shiftingsub circuits to stop generating corresponding clock control signal tothe first left GOA unit or the first right GOA unit when the left clockline or the right clock line has the short circuit condition. Thus, theover current protection circuit according to the embodiment of thepresent invention will not provide the first left clock control signalCK1-L to the first left GOA unit but the first right clock controlsignal CK1-R outputted to the first right GOA unit will not be affectedwhen the first clock line of the first left GOA unit is in shortcircuit. The TFTs driven by the left GOA unit and the right GOA unitstill can work normally. Meanwhile, the clock control signal of the leftGOA unit and the right GOA unit of other stages will not be affected,either to ensure the normal display of the liquid crystal panel.

Optionally, referring to FIG. 2, FIG. 2 is a diagram of another overcurrent protection circuit disclosed by the embodiment of the presentinvention. As shown in FIG. 2, the over current protection circuit shownin this embodiment is substantially the same as the over currentprotection circuit shown in FIG. 1. Please refer to the description ofthe over current protection circuit shown in FIG. 1 in the aboveembodiment, and the details are not described here, again.

Furthermore, the difference is that in the over current circuitdescribed in the embodiment shown in FIG. 2, the first left levelshifting sub circuit 31 comprises a first left controlling circuit 311and a first left amplifying circuit 312, when the first left levelshifting sub circuit 31 normally works, a clock controller (not shown infigure, so called logic board TCON) inputs a clock signal to the firstleft controlling circuit 311. The first left amplifying circuit 312amplifies the clock signal received by the first left controllingcircuit 311 into the first left clock control signal CK1-L and outputsthe same to the first left GOA unit. When the first left over currentprotection sub circuit 11 detects that the first left driving current onthe first left clock line is larger than the predetermined currentthreshold value, it outputs the first left stopping control signal tothe first left controlling circuit 311 of the first left level shiftingsub circuit 31. When the first left controlling circuit 311 receives thefirst left stopping control signal, the first left controlling circuit311 controls the first left amplifying circuit 312 to stop working.

Similarly, the first right level shifting sub circuit 41 comprises afirst right controlling circuit 411 and a first right amplifying circuit412, when the first right level shifting sub circuit 41 normally works,the first left amplifying circuit 312 amplifies the clock signalinputted to the first right controlling circuit 411 by the clockcontroller into the first right clock control signal CK1-R and outputsthe same to the first right GOA unit. When the first right over currentprotection sub circuit 21 detects that the first right driving currenton the first right clock line is larger than the predetermined currentthreshold value, it outputs the first right stopping control signal tothe first right controlling circuit 411 of the first right levelshifting sub circuit 41. When the first right controlling circuit 411receives the first right stopping control signal, the first rightcontrolling circuit 411 controls the first right amplifying circuit 412to stop working.

Optionally, referring to FIG. 3, FIG. 3 is a specific diagram of oneanother over current protection circuit disclosed by the embodiment ofthe present invention. As shown in FIG. 3, the over current protectioncircuit shown in this embodiment comprises a left over currentprotection circuit 10 and a right over current protection circuit 20.The left over current protection circuit 10 comprises N left overcurrent protection sub circuits (also named as left fuses) (the firstleft over current protection sub circuit 11, the second left overcurrent protection sub circuit 12, . . . , the Nth left over currentprotection sub circuit 1N shown in FIG. 3). The right over currentprotection circuit 20 comprises N right over current protection subcircuits (also named as left fuses) (the first right over currentprotection sub circuit 21, the second right over current protection subcircuit 22, . . . , the Nth right over current protection sub circuit 2Nshown in FIG. 1).

The over current protection circuit is applied in a substrate array rowdriving gate driver on array (GOA) circuit having a dual drivingfunction. The GOA circuit having the dual driving function comprises Nleft GOA units which are cascade coupled, N right GOA units which arecascade coupled, a left level shifting circuit 30 and a right levelshifting circuit 40. Both the GOA unit at the left and the GOA unit atthe right of the same stage correspond to the TFTs of the same row. Theleft level shifting circuit 30 comprises N left level shifting subcircuits (the first left level shifting sub circuit 31, the second leftlevel shifting sub circuit 32, . . . , the Nth left level shifting subcircuit 3N shown in FIG. 3). The right level shifting circuit 40comprises N right level shifting sub circuits (the first right levelshifting sub circuit 41, the second right level shifting sub circuit 42,. . . , the Nth right level shifting sub circuit 4N shown in FIG. 3).Each left GOA unit is driven by the clock control signal outputted bythe corresponding left level shifting sub circuit and each right GOAunit is driven by the clock control signal outputted by thecorresponding right level shifting sub circuit.

In the following, the left GOA unit and the right GOA unit correspondingto the TFTs of the first row are taken as an illustration. The firstleft GOA unit is any one of the N left GOA units, and the first rightGOA unit is any one of the N right GOA units. Specifically, the firstleft GOA unit and the output end of the first left level shifting subcircuit 31 are coupled through the first left clock line and a firstleft fuse 11 is coupled to the first left clock line in series; thefirst right GOA unit and the first right level shifting sub circuit 41are coupled through a first right clock line, a first right fuse 21 iscoupled to the first right clock line in series; the first left levelshifting sub circuit 31 is a left level shifting sub circuitcorresponding to the first left GOA unit and the first right levelshifting sub circuit 41 is a left level shifting sub circuitcorresponding to the first right GOA unit.

When the first left level shifting sub circuit 31 works, the first leftlevel shifting sub circuit 31 generates a first left clock controlsignal CK1-L. The first left clock control signal CK1-L is outputted tothe first left GOA unit through the first left clock line to control onand off of the TFTs of the row.

Similarly, when the first right level shifting sub circuit 41 works, thefirst right level shifting sub circuit 41 generates a first right clockcontrol signal CK1-R. The first right clock control signal CK1-R isoutputted to the first right GOA unit through the first right clockline. The timings (sequences) of the first left clock control signalCK1-L and the first right clock control signal CK1-R are the same.

The first left fuse 11 is self fused when the first left driving currentI1-L on the first left clock line is larger than a predetermined currentthreshold value (the fusing current of the fuse) to control the firstleft level shifting sub circuit 31 to stop outputting the first leftclock control signal CK1-L to the first left GOA unit. Then, the outputof the first left level shifting sub circuit 31 is in Hi-Z(high-impedance state). Similarly, the first right fuse 21 controls theright level shifting sub circuit 41 to stop working when the first rightdriving current I1-R on the first right clock line is larger than thepredetermined current threshold value. Indirectly, the first left fusealso functions to detect the first left driving current on the firstleft clock line.

Furthermore, for the first left GOA unit and the first right GOA unit ofthe same stage, the fusing current of the first left fuse 11 (the firstleft over current protection sub circuit) and the fusing current of thefirst right fuse 21 (the first right over current protection subcircuit) are the same.

Preferably, both the first left fuse 11 and the first right fuse 21 arerecoverable fuses. Specifically, when the first left driving currentI1-L on the first left clock line is smaller than the predeterminedcurrent threshold value (the fusing current of the fuse), the fuseresumes a good on-state so as to sustainably implementing short circuitprotection to the first left clock line coupled to the first left GOAunit.

The over current protection circuit in FIG. 3 also can keep the firstright clock control signal outputted to the first right GOA unit notbeing affected and the GOA unit of the stage still can work normallywhen the first left clock line of the first left GOA unit is in shortcircuit. Under such circumstance, the structure of the first left levelshifting sub circuit 31 and the first right level shifting sub circuit41 in FIG. 3 may also be replaced by the structure similar to that inFIG. 2 and details are not described here, again. The difference is thatwhen the first left over current protection sub circuit is fused, thefirst left controlling circuit controls the first left amplifyingcircuit to stop working; when the first right over current protectionsub circuit is fused, the first right controlling circuit controls thefirst right amplifying circuit to stop working.

The embodiment of the present invention further provides a liquidcrystal display comprising an over current protection circuit as shownin any one of FIGS. 1-3. The GOA circuit having dual driving function isarranged at the left side and the right side of the active area of theliquid crystal display. The over current protection circuit can bereferred to the aforementioned description shown in FIG. 1 to FIG. 3.The repeated description is omitted here.

In the description of the present specification, the reference terms,“one embodiment”, “some embodiments”, “an illustrative embodiment”, “anexample”, “a specific example”, or “some examples” mean that suchdescription combined with the specific features of the describedembodiments or examples, structure, material, or characteristic isincluded in the utility model of at least one embodiment or example. Inthe present specification, the terms of the above schematicrepresentation do not certainly refer to the same embodiment or example.Meanwhile, the particular features, structures, materials, orcharacteristics which are described may be combined in a suitable mannerin any one or more embodiments or examples.

The detail description has been introduced above for the over currentprotection circuit and the liquid crystal display provided by theembodiment of the invention. Herein, a specific case is applied in thisarticle for explain the principles and specific embodiments of thepresent invention have been set forth. The description of the aforesaidembodiments is only used to help understand the method of the presentinvention and the core idea thereof; meanwhile, for those of ordinaryskill in the art, according to the idea of the present invention, thereshould be changes either in the specific embodiments and applicationsbut in sum, the contents of the specification should not be limitationto the present invention.

What is claimed is:
 1. An over current protection circuit, applied in asubstrate array row driving gate driver on array (GOA) circuit having adual driving function, wherein the GOA circuit having the dual drivingfunction comprises N left GOA units, N right GOA units, a left levelshifting circuit and a right level shifting circuit, wherein the overcurrent protection circuit comprises a left over current protectioncircuit and a right over current protection circuit, the left overcurrent protection circuit comprises N left over current protection subcircuits and the right over current protection circuit comprises N rightover current protection sub circuits, the left level shifting circuitcomprises N left level shifting sub circuits and the right levelshifting circuit comprises N right level shifting sub circuits, each ofthe left GOA units is driven by a corresponding left level shifting subcircuit and each of the right GOA units is driven by a correspondingright level shifting sub circuit, N is an positive integer; a first leftGOA unit and a first left level shifting sub circuit are coupled througha first left clock line, a first left over current protection subcircuit is coupled to the first left clock line and the first left levelshifting sub circuit; a first right GOA unit and a first right levelshifting sub circuit are coupled through a first right clock line, afirst right over current protection sub circuit is coupled to the firstright clock line and the first right level shifting sub circuit; thefirst left GOA unit is any one of the N left GOA units and the firstright GOA unit is any one of the N right GOA units; when the first leftlevel shifting circuit works, the first left level shifting circuitgenerates a first left clock control signal to be outputted to the firstleft GOA unit through the first left clock line; when the first rightlevel shifting circuit works, the first right level shifting circuitgenerates a first right clock control signal to be outputted to thefirst right GOA unit through the first right clock line; the first leftclock control signal has the same timing as the first right clockcontrol signal; the first left over current protection sub circuitdetects a first left driving current on the first left clock line andcontrols the first left level shifting sub circuit to stop working whenthe first left driving current is larger than a predetermined currentthreshold value; the first right over current protection sub circuitdetects a first right driving current on the first right clock line andcontrols the first right level shifting sub circuit to stop working whenthe first right driving current is larger than the predetermined currentthreshold value.
 2. The over current protection circuit according toclaim 1, wherein the first left over current protection sub circuitoutputs a first left stopping control signal to the first left levelshifting sub circuit when first left driving current is larger than thepredetermined current threshold value to control the first left levelshifting sub circuit to stop working.
 3. The over current protectioncircuit according to claim 2, wherein the first left level shifting subcircuit comprises a first left controlling circuit and a first leftamplifying circuit, when the first left level shifting sub circuitworks, the first left amplifying circuit converts a clock signalinputted to the first left controlling circuit by a clock controllerinto the first left clock control signal; the first left controllingcircuit controls the first left amplifying circuit to stop working whenthe first left controlling circuit receives the first left stoppingcontrol signal.
 4. The over current protection circuit according toclaim 1, wherein the first right over current protection sub circuitoutputs a first right stopping control signal to the first right levelshifting sub circuit when first right driving current is larger than thepredetermined current threshold value to control the first right levelshifting sub circuit to stop working.
 5. The over current protectioncircuit according to claim 4, wherein the first right level shifting subcircuit comprises a first right controlling circuit and a first rightamplifying circuit, when the first right level shifting sub circuitworks, the first right amplifying circuit converts a clock signalinputted to the first right controlling circuit by a clock controllerinto the first right clock control signal; the first right controllingcircuit controls the first right amplifying circuit to stop working whenthe first right controlling circuit receives the first right stoppingcontrol signal.
 6. An over current protection circuit, applied in asubstrate array row driving gate driver on array (GOA) circuit having adual driving function, wherein the GOA circuit having the dual drivingfunction comprises N left GOA units, N right GOA units, a left levelshifting circuit and a right level shifting circuit, wherein the overcurrent protection circuit comprises a left over current protectioncircuit and a right over current protection circuit, the left overcurrent protection circuit comprises N left over current protection subcircuits and the right over current protection circuit comprises N rightover current protection sub circuits, both the left over currentprotection sub circuits and the right over current protection subcircuits are fuses, the left level shifting circuit comprises N leftlevel shifting sub circuits and the right level shifting circuitcomprises N right level shifting sub circuits, each of the left GOAunits is driven by a corresponding left level shifting sub circuit andeach of the right GOA units is driven by a corresponding right levelshifting sub circuit, N is an positive integer; a first left GOA unitand a first left level shifting sub circuit are coupled through a firstleft clock line, a first left over current protection sub circuit iscoupled to the first left clock line in series; a first right GOA unitand a first right level shifting sub circuit are coupled through a firstright clock line, a first right over current protection sub circuit iscoupled to the first right clock line in series; the first left GOA unitis any one of the N left GOA units and the first right GOA unit is anyone of the N right GOA units; when the first left level shifting circuitworks, the first left level shifting circuit generates a first leftclock control signal to be outputted to the first left GOA unit throughthe first left clock line; when the first right level shifting circuitworks, the first right level shifting circuit generates a first rightclock control signal to be outputted to the first right GOA unit throughthe first right clock line; the first left clock control signal has thesame timing as the first right clock control signal; the first left overcurrent protection sub circuit is fused when the first left clockcontrol signal on the first left clock line is larger than apredetermined current threshold value to stop the first left levelshifting sub circuit outputting the first left clock control signal tothe first left GOA unit; the first right over current protection subcircuit is fused when the first right clock control signal on the firstright clock line is larger than the predetermined current thresholdvalue to stop the first right level shifting sub circuit outputting thefirst right clock control signal to the first right GOA unit.
 7. Theover current protection circuit according to claim 6, wherein both thefirst left over current protection sub circuit and the first right overcurrent protection sub circuit are recoverable fuses.
 8. The overcurrent protection circuit according to claim 6, wherein the first leftlevel shifting sub circuit comprises a first left controlling circuitand a first left amplifying circuit, when the first left level shiftingsub circuit works, the first left amplifying circuit converts a clocksignal inputted to the first left controlling circuit by a clockcontroller into the first left clock control signal; the first leftcontrolling circuit controls the first left amplifying circuit to stopworking when the first left over current protection sub circuit isfused.
 9. The over current protection circuit according to claim 6,wherein the first right level shifting sub circuit comprises a firstright controlling circuit and a first right amplifying circuit, when thefirst right level shifting sub circuit works, the first right amplifyingcircuit converts a clock signal inputted to the first right controllingcircuit by a clock controller into the first right clock control signal;the first right controlling circuit controls the first right amplifyingcircuit to stop working when the first right over current protectioncircuit is fused.
 10. A liquid crystal display, comprising a substratearray row driving gate driver on array (GOA) circuit having a dualdriving function and an over current protection circuit, wherein the GOAcircuit having the dual driving function comprises N left GOA units, Nright GOA units, a left level shifting circuit and a right levelshifting circuit, wherein the over current protection circuit comprisesa left over current protection circuit and a right over currentprotection circuit, the left over current protection circuit comprises Nleft over current protection sub circuits and the right over currentprotection circuit comprises N right over current protection subcircuits, both the left over current protection sub circuits and theright over current protection sub circuits are fuses, the left levelshifting circuit comprises N left level shifting sub circuits and theright level shifting circuit comprises N right level shifting subcircuits, each of the left GOA units is driven by a corresponding leftlevel shifting sub circuit and each of the right GOA units is driven bya corresponding right level shifting sub circuit, N is an positiveinteger; a first left GOA unit and a first left level shifting subcircuit are coupled through a first left clock line, a first left overcurrent protection sub circuit is coupled to the first left clock linein series; a first right GOA unit and a first right level shifting subcircuit are coupled through a first right clock line, a first right overcurrent protection sub circuit is coupled to the first right clock linein series; the first left GOA unit is any one of the N left GOA unitsand the first right GOA unit is any one of the N right GOA units; whenthe first left level shifting circuit works, the first left levelshifting circuit generates a first left clock control signal to beoutputted to the first left GOA unit through the first left clock line;when the first right level shifting circuit works, the first right levelshifting circuit generates a first right clock control signal to beoutputted to the first right GOA unit through the first right clockline; the first left clock control signal has the same timing as thefirst right clock control signal; the first left over current protectionsub circuit is fused when the first left clock control signal on thefirst left clock line is larger than a predetermined current thresholdvalue to stop the first left level shifting sub circuit outputting thefirst left clock control signal to the first left GOA unit; the firstright over current protection sub circuit is fused when the first rightclock control signal on the first right clock line is larger than thepredetermined current threshold value to stop the first right levelshifting sub circuit outputting the first right clock control signal tothe first right GOA unit.
 11. The liquid crystal display according toclaim 10, wherein both the first left over current protection subcircuit and the first right over current protection sub circuit arerecoverable fuses.
 12. The liquid crystal display according to claim 10,wherein the first left level shifting sub circuit comprises a first leftcontrolling circuit and a first left amplifying circuit, when the firstleft level shifting sub circuit works, the first left amplifying circuitconverts a clock signal inputted to the first left controlling circuitby a clock controller into the first left clock control signal; thefirst left controlling circuit controls the first left amplifyingcircuit to stop working when the first left over current protection subcircuit is fused.
 13. The liquid crystal display according to claim 10,wherein the first right level shifting sub circuit comprises a firstright controlling circuit and a first right amplifying circuit, when thefirst right level shifting sub circuit works, the first right amplifyingcircuit converts a clock signal inputted to the first right controllingcircuit by a clock controller into the first right clock control signal;the first right controlling circuit controls the first right amplifyingcircuit to stop working when the first right over current protectioncircuit is fused.